 (at the computer)
 (at the computer)
24 PIN MALE EDGE (DZM 12 DREH) at the computer.
| Pin | Name | Description | 
|---|---|---|
| 1 | GND | Ground | 
| 2 | +5V | +5 VDC (100 mA max) | 
| 3 | /RESET | Reset, will force a Cold Start. Also a reset output for devices. | 
| 4 | CNT1 | Counter 1, from CIA #1 | 
| 5 | SP1 | Serial Port 1, from CIA #1 | 
| 6 | CNT2 | Counter 2, from CIA #2 | 
| 7 | SP2 | Serial Port 2, from CIA #2 | 
| 8 | /PC2 | Handshaking line, from CIA #2 | 
| 9 | ATN | Serial Attention In | 
| 10 | +9V AC | +9 VAC (+ phase) (100 mA max) | 
| 11 | +9V AC | +9 VAC (- phase) (100 mA max) | 
| 12 | GND | Ground | 
| A | GND | Ground | 
| B | /FLAG2 | Flag 2 | 
| C | PB0 | Data 0 | 
| D | PB1 | Data 1 | 
| E | PB2 | Data 2 | 
| F | PB3 | Data 3 | 
| H | PB4 | Data 4 | 
| J | PB5 | Data 5 | 
| K | PB6 | Data 6 | 
| L | PB7 | Data 7 | 
| M | PA2 | PA2 | 
| N | GND | Ground | 
Note: 0.156" (3.96mm) contact spacing.
The Commodore 64 gives you complete control over Port B on VIA chip #1. Eight lines for input or output are available, as well as 2 lines for handshaking with an outside device. The I/O lines for Port B are controlled by two locations. One is the port itself, and is located at 56577 ($DD01 hex). Naturally you PEEK it to read an input, or POKE it to set an output. Each of the eight I/O lines can be set up as either an input or an output by setting the data direction register properly. It is located at 56579 ($DD03 hex).
| Contributor: | Joakim Ögren, Nikolas Engström, Arwin Vosselman, Jestin Nesselroad, Larry Anderson | 
| Source: | Commodore 64 Programmer's Reference Guide | 
| NT Rautanen Tietokonesivut: Commodore | 
  Copyright © The Hardware Book Team 1996-2004.
  May be copied and redistributed, partially or in whole, as appropriate.
  Document last modified: 2002-01-13